Grin Lenses vs Convex

I am interested in comparing the effectiveness of GRIN lenses vs aspheric-convex ones for collimating laser beams. I can imagine some practical advantages however I would be interested in any information comparing the advantage of one method over the other from an optical standpoint.

Thanks,
Fritz

 

Andy
we are setting up a delicate fiber laser focusing system. The beam is being crunched down from 4mm to about .05mm. This will be deployed in a mecahnically rough (marine) envirionment. The commercial grin lens devices are attractive, self contained etc. But from a technical point of view my understanding, which is somewhat dated, is that some basic bi-convex lens constructs can superceed the quality of a grin lens with regards to spherical ab.